package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Override
    public Result queryBlogById(Long id) {
        // 根据id查询blog
        Blog blog = getById(id);
        if (blog == null){
            return Result.fail("笔记不存在");
        }
        //查询blog有关的用户
        queryBlogUser(blog);
        //查询blog是否被点赞
        isBlogLiked(blog);
        return Result.ok(blog);

    }


    @Override
    public Result queryHotBlog(Integer current) {
        //根据用户查询
        Page<Blog> page = query().orderByDesc("liked").page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        //获取当前页数据
        List<Blog> records = page.getRecords();
        //查询用户
        records.forEach(blog -> {
            queryBlogUser(blog);
            isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    @Override
    public Result likeBlog(Long id) {
        //利用redis实现点赞功能(set)
        //1.获取当前登录用户
        Long userId = UserHolder.getUser().getId();
        //2.判断当前用户是否已经点赞
        String key = "blog:liked:" + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        //3.如果未点赞，可以点赞
        if(score == null){
            //4.数据库点赞数+1
            boolean updateSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            if(updateSuccess){
                //5.保存用户到redis set集合 sadd blog:liked:5 userId
                stringRedisTemplate.opsForZSet().add(key, userId.toString(), System.currentTimeMillis());
            }
        }else {
            //6.如果已点赞，取消点赞
            //7.数据库点赞数-1
            boolean updateSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            if(updateSuccess){
                //8.set集合中移除用户
                stringRedisTemplate.opsForZSet().remove(key, userId.toString());
            }
        }
        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        //查询top5点赞用户
        String key = "blog:liked:" + id;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        //解析出用户id
        if (top5 == null || top5.isEmpty()){
            return Result.ok(Collections.EMPTY_LIST);
        }
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        //根据id查询用户
        List<UserDTO> list = userService.listByIds(ids)
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());

        return Result.ok(list);
    }

    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    private void isBlogLiked(Blog blog) {
        //1.获取当前登录用户
        Long userId = UserHolder.getUser().getId();
        //2.判断当前用户是否已经点赞
        String key = "blog:liked:" + blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }
}
